Upstaters want to pull the plug on a planned megapower line that would snake across 200 miles and feed electricity to the energy-hungry Big Apple – an upstate-downstate battle that even Mayor Bloomberg is getting involved in.

The private project, New York Regional Interconnection, has sparked a wave of protests in counties that would be affected by the above-ground, $1.6 billion transmission line – whose 10-story towers have residents up in arms over potentially reduced property values, hampered tourism and health hazards.

“I think there are plenty of other alternatives to providing power to the downstate region,” said state Sen. James Seward, a Republican from Otsego County. “I know of no one who favors this proposed line . . . in the affected area.”

Sen. Thomas Libous (R-Binghamton) said the upstate areas will not benefit in the slightest and said, “It has unfortunately become an upstate-downstate issue . . . This is not for the public good at all.”

A spokeswoman for the city’s Economic Development Corp. said, “We’d need more information on this particular proposal, but we generally support the concept of transmission lines from upstate or New Jersey into the city.”

NYRI officials have started seeking approval with the state Public Service Commission for the 1,200-megawatt transmitter, which would give the company the power to use eminent domain to scoop up private land needed for the route and have the line running in five years.

But upstate lawmakers managed to push through in the final days of the state legislative session a bill to prevent the NYRI from using eminent domain – a huge blow to the project if Gov. Pataki signs it, forcing the company to work out individual deals with land owners.

Bloomberg aides said the mayor opposes the bill and that he will write to Pataki this week asking him to veto it, on the grounds that it would hamper the city’s long-term energy needs. Pataki aides said he has not yet received the bill and has to review it.

Jonathan Pierce, an NYRI spokesman, insisted the company had “talked to a lot of people” downstate who support the transmission line, but he refused to name any.

The privately funded project, whose lead backer is Toronto-based, would start in Oneida County, wind through the Catskills and end in Orange County.

Pataki and state Attorney General Eliot Spitzer, the gubernatorial race front-runner, have stayed mum on whether they support the project, saying it needs more review.

After keeping quiet for weeks, Sens. Charles Schumer and Hillary Rodham Clinton recently said they have concerns about the project.